Scientists create 'black holes' on Earth

Thanks to a legion of science fiction stories, black holes are easily among the most terrifying objects in the universe. It is easy to understand why: these mysterious collapsed stars suck in and destroy everything around them. Get too close and nothing in the universe could save you from their clutches.

Fortunately, real black holes only exist in the depths of space, too far from the Earth to be of much concern. But an American physicist has put forward the idea that an experiment here on Earth regularly creates objects that bear a striking resemblance to real black holes, albeit tiny ones.

Horatiu Nastase of Brown University in Providence, Rhode Island, thinks that the intense fireballs created in an atom-smashing experiment at the Brookhaven National Laboratory in New York have remarkable similarities to the celestial phenomena.

But, worry not, the fireballs are nothing dangerous - they last for a mere 100,000 billion billionths of a second and do not seem to have much impact on the matter around them.

A real black hole is made from a massive star that has collapsed on itself - the gravitational force it exerts on the space around it means that matter is drawn towards it.

Prof Nastase's work is purely theoretical. But even if it proved to be completely correct, the amount of matter involved in typical particle accelerator experiments is so small that any gravitational effects of the mini "black hole" would be inconsequential.

"A black hole that can do interesting or scary things has to be quite large," said Andrew Jaffe, a cosmologist at Imperial College.

The Relativistic Heavy Ion Collider at Brookhaven throws the nuclei of large atoms, such as gold, together at close to the speed of light. The ensuing collision creates enough heat to produce a plasma 300 million times hotter than the surface of the sun.

For the briefest of moments, the nuclei break down into their constituent bits - particles called quarks and gluons - a state of matter that has not existed since a microsecond after the big bang that began the universe.

Analysing this process usually involves some horribly complicated quantum physics. But Prof Nastase decided instead to try a different tack and use string theory.

This bizarre idea is the prime candidate to solve the biggest problem in theoretical physics: how to describe the fundamental forces of nature in a single, coherent theory.

He showed that the core of the fireball had some of the characteristics of a black hole - 10 times more particles were being absorbed by the fireball than any quantum physics calculations could predict.

He said the particles were disappearing into the fireball before coming back out again as thermal radiation, rather as real black holes suck in matter from around them and re-emit "Hawking" radiation.

The problem for string theorists has always been that their work does not have experimental data to back it up, so many physicists are sceptical. But Prof Nastase's idea could begin to turn the tide.

Whatever happens, modern physics cannot create any damaging black holes here on Earth. "A few particles that you can push together in an accelerator ain't going to hurt anybody," Dr Jaffe said.